assignee's French Patent No. FR-A-2 607 368 provides a description of conventionally-known alpine ski boots of this kind whose shell base is comprising two assembled pieces, i.e., a lower part opening upward which extends substantially over the entire length of the boot and may enclose the heel of the skier, and an upper part extending above the front part of the foot and forming a rigid closing cover. The attachment joining the upper closing cover and the lower part of the shell base may comprise any conventional assembly means, particularly reciprocal rivets. Furthermore, the boot is equipped with an internal foot position maintenance device which makes it possible to hold the skier's foot more or less tightly within the shell base, in order to create firm contact between the skier's foot and the boot when skiing.